SETH (Heb. shēth, “appointed,” i.e., “substituted”) Adam’s third son; father of Enosh (Gen.4.25-Gen.4.26; Gen.5.3-Gen.5.8). His name signifies that he was considered a “substitute” for Abel (Gen.4.25). His birth recalled man’s tragic loss of the divine image (Gen.5.1-Gen.5.2). He became the founder of the line of faith (Gen.4.26; Luke.3.38).
Because the genealogies in Genesis 4:18-22 and 5:3-32 both contain Enoch and Lamech, some think one derives from the so-called “J” document and the other from the “P” document. However, the differences would suggest that they are two entirely different lists rather than one list confused in transmission through two different traditions.
Some think he was named Seth (4:25) because he took the place of the murdered brother, Abel. However, this presents some linguistic problems, so perhaps rather than being derived from the root shath, “to appoint,” the name was selected because of its assonance with that verb.
2. An unknown person (Num 24:17 where ASV translates it “tumult”) who is the ancestor of a people mentioned by Balaam as enemies of Israel. Albright (BASOR, LXXXIII, 1941, 34) identifies them with the S̆wtw of Egyp. execration texts.
International Standard Bible Encyclopedia (1915)
seth, sheth (sheth; Seth):
(1) The son born to Adam and Eve after the death of Abel (Ge 4:25 f; 5:3 ff; 1Ch 1:1; Sirach 49:16; Lu 3:38). In Ge 4:25 the derivation of the name is given. Eve "called his name Seth: For, said she, God hath appointed (shath) me another seed instead of Abel." In 1Ch 1:1 the King James Version, the form is "Sheth"; elsewhere in the King James Version and in the Revised Version (British and American) throughout the form is "Seth."
(2) the King James Version "the children of Sheth," the Revised Version (British and American) "the sons of tumult." According to the King James Version rendering, the name of an unknown race mentioned in Balaam’s parable (Nu 24:17).